aboutsummaryrefslogtreecommitdiff
path: root/arch/s390/crypto/sha256_s390.c
blob: c728bd0ae1ed987b8b222f8df7ce02a2fabcabe8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
/*
 * Cryptographic API.
 *
 * s390 implementation of the SHA256 Secure Hash Algorithm.
 *
 * s390 Version:
 *   Copyright IBM Corp. 2005,2007
 *   Author(s): Jan Glauber (jang@de.ibm.com)
 *
 * Derived from "crypto/sha256_generic.c"
 * and "arch/s390/crypto/sha1_s390.c"
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/crypto.h>

#include "crypt_s390.h"

#define SHA256_DIGEST_SIZE	32
#define SHA256_BLOCK_SIZE	64

struct s390_sha256_ctx {
	u64 count;		/* message length */
	u32 state[8];
	u8 buf[2 * SHA256_BLOCK_SIZE];
};

static void sha256_init(struct crypto_tfm *tfm)
{
	struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);

	sctx->state[0] = 0x6a09e667;
	sctx->state[1] = 0xbb67ae85;
	sctx->state[2] = 0x3c6ef372;
	sctx->state[3] = 0xa54ff53a;
	sctx->state[4] = 0x510e527f;
	sctx->state[5] = 0x9b05688c;
	sctx->state[6] = 0x1f83d9ab;
	sctx->state[7] = 0x5be0cd19;
	sctx->count = 0;
}

static void sha256_update(struct crypto_tfm *tfm, const u8 *data,
			  unsigned int len)
{
	struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
	unsigned int index;
	int ret;

	/* how much is already in the buffer? */
	index = sctx->count & 0x3f;

	sctx->count += len;

	if ((index + len) < SHA256_BLOCK_SIZE)
		goto store;

	/* process one stored block */
	if (index) {
		memcpy(sctx->buf + index, data, SHA256_BLOCK_SIZE - index);
		ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf,
				      SHA256_BLOCK_SIZE);
		BUG_ON(ret != SHA256_BLOCK_SIZE);
		data += SHA256_BLOCK_SIZE - index;
		len -= SHA256_BLOCK_SIZE - index;
	}

	/* process as many blocks as possible */
	if (len >= SHA256_BLOCK_SIZE) {
		ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, data,
				      len & ~(SHA256_BLOCK_SIZE - 1));
		BUG_ON(ret != (len & ~(SHA256_BLOCK_SIZE - 1)));
		data += ret;
		len -= ret;
	}

store:
	/* anything left? */
	if (len)
		memcpy(sctx->buf + index , data, len);
}

/* Add padding and return the message digest */
static void sha256_final(struct crypto_tfm *tfm, u8 *out)
{
	struct s390_sha256_ctx *sctx = crypto_tfm_ctx(tfm);
	u64 bits;
	unsigned int index, end;
	int ret;

	/* must perform manual padding */
	index = sctx->count & 0x3f;
	end = (index < 56) ? SHA256_BLOCK_SIZE : (2 * SHA256_BLOCK_SIZE);

	/* start pad with 1 */
	sctx->buf[index] = 0x80;

	/* pad with zeros */
	index++;
	memset(sctx->buf + index, 0x00, end - index - 8);

	/* append message length */
	bits = sctx->count * 8;
	memcpy(sctx->buf + end - 8, &bits, sizeof(bits));

	ret = crypt_s390_kimd(KIMD_SHA_256, sctx->state, sctx->buf, end);
	BUG_ON(ret != end);

	/* copy digest to out */
	memcpy(out, sctx->state, SHA256_DIGEST_SIZE);

	/* wipe context */
	memset(sctx, 0, sizeof *sctx);
}

static struct crypto_alg alg = {
	.cra_name	=	"sha256",
	.cra_driver_name =	"sha256-s390",
	.cra_priority	=	CRYPT_S390_PRIORITY,
	.cra_flags	=	CRYPTO_ALG_TYPE_DIGEST,
	.cra_blocksize	=	SHA256_BLOCK_SIZE,
	.cra_ctxsize	=	sizeof(struct s390_sha256_ctx),
	.cra_module	=	THIS_MODULE,
	.cra_list	=	LIST_HEAD_INIT(alg.cra_list),
	.cra_u		=	{ .digest = {
	.dia_digestsize	=	SHA256_DIGEST_SIZE,
	.dia_init	=	sha256_init,
	.dia_update	=	sha256_update,
	.dia_final	=	sha256_final } }
};

static int init(void)
{
	if (!crypt_s390_func_available(KIMD_SHA_256))
		return -EOPNOTSUPP;

	return crypto_register_alg(&alg);
}

static void __exit fini(void)
{
	crypto_unregister_alg(&alg);
}

module_init(init);
module_exit(fini);

MODULE_ALIAS("sha256");

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA256 Secure Hash Algorithm");